Heretofore, various herbicidal compounds are used for the lawns. For example, in management of a lawn at a golf course, it has become indispensable to use a herbicidal compound. At a golf course, plural types of turfgrasses are planted in many cases, and it is often a case where turfgrass less sensitive to a herbicidal compound to be used and turfgrass highly sensitive thereto are used in combination. In such a case, a certain restriction is required in the use of the herbicidal compound, and the situation has not been necessarily satisfactory from the viewpoint of the operation efficiency, costs, etc.
Flazasulfuron is known as a herbicidal compound (Patent Document 1). Warm-season turfgrass such as mascarenegrass or Japanese lawngrass is less sensitive to flazasulfuron and thus is safe thereto. Further, flazasulfuron can control unwanted plants and thus is an excellent compound. On the other hand, cool-season turfgrass such as bentgrass, bluegrass or ryegrass is relatively highly sensitive to flazasulfuron, and flazasulfuron may sometimes present undesirable effects thereto.
As mentioned above, in a golf course, plural types of turfgrasses are planted in many cases. For example, warm-season turfgrass which is safe to flazasulfuron may be planted in fairways, etc., and cool-season turfgrass which is highly sensitive to flazasulfuron, may be planted in putting greens, etc. Flazasulfuron is usually applied to a site where warm-season turfgrass is planted, but immediately after the application or even after expiration of a certain period after the application, in a situation where morning dew or the like is observed, flazasulfuron is likely to attach to soles of shoes of players walking on the warm-season turfgrass, and if the players walk on the green in such a state, undesirable effects may be brought about against the cool-season turfgrass planted in the green. Further, other than via soles of shoes of players, etc., for example, via a chemical treatment tool to apply various chemicals, a watering tool to sprinkle water to turfgrass, etc., or a lawn-mowing tool such as a lawn mower, undesirable effects may be brought about on the cool-season turfgrass.
Such a problem is not limited to with respect to flazasulfuron and may be present with respect to any herbicidal compound, to which the sensitivity is different depending upon the types of turfgrasses.